1. Field of the Invention
The present invention relates to an information-holding unit on which information carriers with specific information stored therein are mounted.
2. Description of the Related Art
An information-holding unit has been used and made by mounting, on various articles, an information carrier such as a magnetic card, an IC (integrated circuit) card, a bar code, or RFID (Radio Frequency Identification) that stores specific information about such articles. Systems that use such information-holding unit, for example, for identification, collating, management, or conveyance of the above-mentioned articles, are employed in wide-ranging areas such as distribution, FA (Factory Automation), and medical care.
Recently, a non-contact automatic identification system that utilizes RFID techniques capable of reading, without any contact, an IC chip as the information carrier, on which information is written, has been widely used, for example, in product assembly and conveying line systems, inspection lines, product management, product inventory and order management, work information management, and tool management. For example, at manufacturing plants or other locations, the non-contact automatic identification system is used to attach IC chips to tools for machine tools, to prevent errors in attaching the tools to the machine tools, to improve efficiency in arrangement, to register offset information automatically, and to conduct location management. Moreover, PC networks are utilized to share information about manufacturing plants (or job sites), thereby enhancing the efficiency and quality of the production and accumulating processing know-how.
Since the conventional information carrier is generally constructed by mounting one information carrier on an article, if the desired amount of information to be stored is large, one of the possible methods is the method of increasing the storage capacity of the information carrier or having the information carrier carry a code and drawing necessary information from an information server.
However, if the storage capacity of the information carrier is increased, it brings about the drawbacks that it will become expensive and will require longer information transferring time (or time required for sending/receiving information).
In the case of the RFID, the dominant type of RFID saves power in an IC chip by using high-frequency waves to be transmitted as a power source and operates with the saved power as the power source. This type of RFID has the drawback that if the storage capacity of the information carrier is increased, the required driving power should also be increased.